1. Field of the Invention
The present invention generally relates to footwear soles, and more particularly relates to footwear outsoles and tread constructions for footwear outsoles.
2. Related Art
According to the U.S. Bureau of Labor Statistics, slip and fall accidents are the second leading personal injury incident and second cause of accidental death in the United States. For the approximately 10 million work force in the food and preparation serving industry, as reported by the Bureau of Labor Statistics, these incidents represent about 65% of all lost time accidents among employees and more than 50% of all falls are caused by a slippery walking surface. By wearing footwear that includes slip resistant soles, some types of workers can minimize the risk of slip and fall accidents.
The slip resistance of a footwear can be tested using ASTM F1677-96 testing methods. These testing methods utilize the Brungraber Mark 11 testing, which applies both horizontal and vertical forces to a footwear sole simultaneously, resulting in a more thorough slip resistance measurement. These testing methods are well recognized throughout the United States and many other parts of the world.
The focus of the Brungraber testing is to measure the slip resistance of a footwear on dry, wet, and oily/wet surfaces. The tests are conducted on a 4-inch square section of American Olean red quarry tile as a test surface. To generate a slippery surface, testing labs use 0.05 grams (2 drops) of vegetable oil for the oily test. For the oily/wet test, 25 militers of water is added to the 0.05 grams of vegetable oil. A second test uses 0.2 grams (7 drops) of vegetable oil for the oily test with 25 militers of water added for the oily/wet testing. There are also dry tests and wet tests performed on the tile surface.
The slip resistance of a footwear can be affected by both the tread design and the materials of the footwear outsole. A footwear with improved slip resistant properties using tread design, materials, or a combination of tread design and materials would be an advance in the art.